Silicone/adhesive complex whereof the interface has a release force capable of being modulated by electron beam irradiation

ABSTRACT

The invention concerns a silicone/adhesive complex comprising at least a silicone coating applied on a first support and an adhesive coating applied on a second support and whereof the release force of a silicone/adhesive interface is capable of being modulated. The invention is characterised in that its silicone coating is derived from polymerisation and/or crosslinking of polyorganosiloxane monomers, oligomers and/or polymers and said silicone coating further comprises at least an additive regulating the release force of a silicone/adhesive interface and whereof the activity is initiated and capable of being modulated by electron beam irradiation.

[0001] The present invention relates in general to complexes referred toas “self-adhesive” complexes composed especially of a nonstick siliconematrix and of an adhesive coating.

[0002] This type of complex is generally intended for use where thecrosslinked or cured silicone matrix is affixed to a substrate so as tomake it nonstick with respect to the adhesive. This type of complex isespecially applicable in the field of adhesive protective papers,labels, decorative papers and adhesive tapes.

[0003] The silicone oils or resins that have been proposed in order toobtain this type of coating having nonstick properties derive in generalfrom cationic and/or radical crosslinking systems. More particularly,they are monomers, oligomers and/or polymers of the polyorganosiloxanekind comprising functional and reactive radicals capable of formingintrachain and interchain bridges. These systems result, aftercrosslinking, in nonstick coatings which form complexes called“self-adhesive” complexes with adhesives, which are applied to theirsurface after siliconizing.

[0004] An essential property of these silicone/adhesive complexes isthat they allow an easy release of the adhesive from the siliconecoating when they are used.

[0005] Depending on the nature of the applications contemplated for thistype of complex, it is desirable to be able to vary the release forceneeded to separate the silicone coating from the adhesive coating.

[0006] This release force may in this case be quantified. Although itsvalues may vary significantly depending on the measurement methodadopted, overall it can be characterized as follows for a low releaserate, that is to say of around 30 cm/min, and using the FTM3 method:

[0007] a release force of less than 15 g/cm is regarded as low;

[0008] a release force of greater than 15 g/cm and less than 70 g/cm isregarded as moderate; and

[0009] a release force of greater than 70 g/cm and preferably less than200 g/cm is regarded as high.

[0010] It is an object of the present invention specifically to providea silicone/adhesive complex whose release force may be adjusted asrequired and preferably to a value lying within the abovementionedrange, namely between 15 g/cm and 200 g/cm.

[0011] More specifically, the present invention relates to the field ofcurable and/or crosslinkable adhesive/silicone complexes, the force torelease the interface of which can be varied by means of irradiation byan electron-beam source (electron beam).

[0012] More particularly, a first subject of the present invention is asilicone/adhesive complex comprising at least one silicone coatingapplied to a first substrate and an adhesive coating applied to a secondsubstrate, the force to release a silicone/adhesive interface of whichcan be varied, characterized in that said silicone coating comprises atleast one additive for regulating the force to release asilicone/adhesive interface and the activity of which is initiated andable to be varied by electron-beam irradiation.

[0013] The additive is preferably activated by exposing, if not thecomplex, then at least one silicone/adhesive interface to at least oneelectron beam irradiation. In general, this variation is achieved bymeans of an electron beam source whose intensity is adjusted dependingon the nature of the silicone matrix used.

[0014] According to a first variant, the two substrates consist of twoseparate entities placed so that the silicone coating of the firstsubstrate is in contact with the adhesive coating of the secondsubstrate. This embodiment is in particular illustrated by systemscalled self-adhesive labels. In this particular case, the force torelease the silicone/adhesive interface is exerted when the twosubstrates are being separated.

[0015] In a second variant, the two substrates each consist respectivelyof the two faces of the same entity. This second embodiment is inparticular illustrated by the systems called adhesive tapes. Thenonstick coating, that is to say that based on the silicone matrix, andthe adhesive coating are brought into contact while the substrate isbeing wound up on itself. In this case, the release force is exerted atthe silicone/adhesive interface owing to the effect of a lower facebeing separated from an upper face of the material.

[0016] According to a preferred embodiment of the invention, theadditive for regulating the force to release the silicone/adhesiveinterface adopted within the context of the present invention is chosenfrom:

[0017] (i) organic (meth)acrylate derivatives;

[0018] (ii) alkenyl ethers; and

[0019] (iii) silicones having one or more (meth)acrylate and/or alkenylether functional groups.

[0020] Especially suitable organic acrylics are (meth)acrylate speciesand especially epoxidized (meth)acrylates;(meth)acrylo-glycero-polyesters and multifunctional (meth)acrylates;(meth)acrylo-urethanes; (meth)acrylo-polyethers;(meth)acrylo-polyesters; and (meth)acrylo-acrylics.

[0021] More particularly preferred are trimethylolpropane triacrylate,tripropylene glycol diacrylate and pentaerythritol tetraacrylate.

[0022] With regard to the alkenyl ethers, these are preferably vinylethers. They may be chosen from cyclohexanedimethanol divinyl ether,triethylene glycol divinyl ether (DVE-3), hydroxybutyl vinyl ether,dodecyl vinyl ether and the other vinyl ethers sold by ISP and which arein particular described in patent application WO 99/19371.

[0023] According to a preferred variant of the invention, the additiveused is a silicone having one or more (meth)acrylate and/or alkenylether functional groups.

[0024] As representatives of (meth)acrylate functional groups carried bythe silicone and most particularly suitable for the invention, mentionmay more particularly be made of acrylate, methacrylate, (meth)acrylateether and (meth)acrylate ester derivatives linked to the polysiloxanechain via a Si-C bond. Such acrylate derivatives are especiallydescribed in patents EP 281 718, FR 2 632 960 and EP 940 458.

[0025] As regards the silicone derivatives having alkenyl etherfunctional groups, these are generally derived from a hydrosilylationreaction between oils containing SiH structural units and compoundscarrying alkenyl ether functional groups such as allyl vinyl ethers,allyl vinyloxy ethoxybenzene and the like. This type of compound is e.g.referred to in U.S. Pat. No. 5,340,898.

[0026] The additive is contained in the silicone coating and is ofcourse present in an amount sufficient to regulate the force to releasethe adhesive/silicone interface. It may be present in an amount up to50% by weight of the silicone coating expressed as dry matter.

[0027] However, the additive is preferably employed in an amount ofabout 0.1 to 20% by weight of the total silicone mixture. Of course, theamount of this additive can vary significantly depending on whether ornot it is of a silicone nature.

[0028] Thus, in the particular case in which this additive is an organicacrylate derivative or an alkenyl ether, its amount is generally betweenabout 0.1 and 10% preferably about 0.5 and 5%, and more preferably 1 and3%.

[0029] On the other hand, an additive of the silicone type is preferablyused in an amount up to 20% by weight and preferably 15% by weight.

[0030] Moreover, it seems that the amount of EB irradiation, generallyexpressed as a radiation dose, is a useful parameter for varying theactivity of the additive defined above and therefore adjusting themagnitude of the release force generated by this additive.

[0031] Thus, in the examples given below, it will be noted that thelevel of adhesion between the silicone coating and the adhesive withwhich it is associated is significantly increased after irradiation.Advantageously, the release force turns out to vary depending on theamount of additive present in the formation and on the intensity ofirradiation.

[0032] The silicone coating generally derives from the polymerizationand/or crosslinking of polyorganosiloxane monomers, oligomers and/orpolymers.

[0033] Actually, this polymerization and/or crosslinking may derive:

[0034] from a hydrosilylation reaction between, on the one hand,monomers, oligomers and/or polymers carrying reactive SiH structuralunits and, on the other hand, monomers, oligomers and/or polymerscarrying an unsaturated aliphatic reactive group;

[0035] from a dehydrogenocondensation reaction between, on the one hand,monomers, oligomers and/or polymers carrying reactive SiH structuralunits and, on the other hand, polymers, oligomers and/or polymerscarrying SiH units and/or reactive groups;

[0036] from a reaction of crosslinking/polymerization of monomers,oligomers and/or polymers carrying reactive units of the acrylate,epoxy, oxetane, dioxolane and/or alkenyl ether reactive units, it beingpossible for this reaction to be carried out by UV irradiation, thermalactivation or by an electron beam.

[0037] In the variant in which the coating derives from ahydrosilylation reaction, the polyorganosiloxane derivatives arepreferably chosen so that the polyorganosiloxane possessing at least oneSiH radical per molecule is a polyorganosiloxane A as defined below andthe polyorganosiloxane possessing at least one unsaturated aliphaticreactive group per molecule satisfies the definition of thepolyorganosiloxane B described below.

[0038] The compounds A are chosen from polyorganohydrogenosiloxanescomprising:

[0039] units of the following formula: $\begin{matrix}{H_{a}W_{b}{SiO}_{\frac{4 - {({a + b})}}{2}}} & (1)\end{matrix}$

[0040]  in which:

[0041] the symbols W, which are similar and/or different, represent:

[0042] a linear or branched alkyl radical containing 1 to 18 carbonatoms, optionally substituted with at least one halogen, preferablyfluorine, the alkyl radicals preferably being methyl, ethyl, propyl,octyl and 3,3,3-trifluoropropyl,

[0043] a cycloalkyl radical containing between 5 and 8 cyclic carbonatoms, optionally substituted with at least one halogen, preferablyfluorine,

[0044] an aryl radical containing between 6 and 12 carbon atoms whichmay optionally be substituted on the aryl part with halogens, alkyls,and/or alkoxyls containing 1 to 3 carbon atoms, preferably phenyl ordichlorophenyl,

[0045] an arylalkyl part having an alkyl part containing between 5 and14 carbon atoms and an aryl part containing between 6 and 12 carbonatoms, optionally substituted on the aryl part by halogens, alkylsand/or alkoxyls containing 1 to 3 carbon atoms,

[0046] a is 1 or 2, b is 0, 1 or 2, with the sum (a+b) having a value ofbetween 1 and 3; and

[0047] optionally, other units of average formula (2): $\begin{matrix}{{Wc}\quad {SiO}_{\frac{4 - c}{2}}} & (2)\end{matrix}$

[0048] in which W has the same meaning as above and c has a value ofbetween 0 and 3.

[0049] The polyorganosiloxane A may be formed from units of formula (1)alone or may further include units of formula (2). It may have a linear,branched or unbranched, cyclic or network structure. The degree ofpolymerization is greater than or equal to 2. More generally, it is lessthan 5000.

[0050] Examples of units of formula (1) are:

H(CH₃)SiO_(1/2), HCH₃SiO_(2/2), H(C₆H₅)SiO_(2/2).

[0051] When these are linear polymers, they essentially consist ofW₂SiO_(2/2) and WHSiO_(2/2) “D” units and W₃SiO_(1/2) and W₂HSiO_(1/2)“M” units.

[0052] These linear polyorganosiloxanes may be oils having a dynamicviscosity at 25° C. of around 1 to 100,000 mPa.s at 25° C., generallyaround 10 to 5000 mPa.s at 25° C., or gums having a molecular mass ofaround 1,000,000.

[0053] When these are cyclic polyorganosiloxanes, they consist ofW₂SiO_(2/2) and WHSiO_(2/2) “D” units, which may be of the dialkylsiloxyor alkylarylsiloxy type. They have a viscosity of around 1 to 5000mPa.s.

[0054] The dynamic viscosity at 25° C. of all the polymers considered inthe present specification may be measured using a Brookfield viscometeraccording to the AFNOR NFT 76 102 standard of February 1972.

[0055] Examples of polyorganosiloxanes A are: dimethyl polysiloxaneshaving hydrogenodimethylsilyl end groups;dimethylhydrogenomethylpolysiloxane copolymers having trimethylsilyl endgroups; dimethylhydrogenomethylpolysiloxane copolymers havinghydrogenodimethylsilyl end groups; hydrogenomethylpolysiloxanes havingtrimethylsilyl end groups; and cyclic hydrogenomethylpolysiloxanes.

[0056] With regard to the polyorganosiloxanes B, namely those having atleast one unsaturated aliphatic reactive group per molecule, these arepreferably selected from polyorganosiloxanes comprising:

[0057] similar or different units of formula (3): $\begin{matrix}{W_{d}^{\prime}Y_{e\quad}{SiO}_{\frac{4 - {({d + e})}}{2}}} & (3)\end{matrix}$

[0058]  in which:

[0059] the symbols W′, which are similar and/or different, correspond tothe same definition as that given above in the case of W,

[0060] the symbols Y are similar or different and represent a C₁-C₁₂linear or branched alkenyl residue having at least one ethylenicallyunsaturated group at the chain end and/or in the chain, and optionallyat least one heteroatom;

[0061] e is equal to 1 or 2, d is equal to 0, 1 or 2 with the sum (d+e)having a value of between 1 and 3;

[0062] and, optionally, other units of average formula (2) as definedabove.

[0063] The polyorganosiloxane B may be formed only from units of formula(3) alone or may further include units of formula (2).

[0064] With regard to the residues Y, these are advantageously chosenfrom the following list: vinyl, propenyl, 3-butenyl, 5-hexenyl,9-decenyl, 10-undecenyl, 5,9-decadienyl and 6,11-dodecadienyl.

[0065] These polyorganosiloxanes may have a linear (branched orunbranched), cyclic or network structure. Their degree of polymerizationis preferably between 2 and 5000.

[0066] When these are linear polymers, they essentially consist ofW′₂SiO_(2/2), W′YSiO_(2/2) and Y₂SiO_(2/2) “D” units, and W′₃SiO_(1/2),W′Y₂SiO_(1/2) and W′₂YSiO_(1/2) “M” units.

[0067] As examples of terminal “M” units mention may be made oftrimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy,dimethylhexenylsiloxy, dimethylethoxysiloxy anddimethylethyltriethoxysiloxy groups.

[0068] As examples of “D” groups mention may be made of dimethylsiloxy,methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy,methylhexenylsiloxy, methyldecenylsiloxy, methyldecadienylsiloxy,methyl-3-hydropropylsiloxy, methyl-3-glycidoxypropylsiloxy,methyl-2-(3′,4′-epoxycyclohexyl)ethylsiloxy, methylbutoxysiloxy,methyl-β-trimethoxysilylethylsiloxy andmethyl-β-triethoxysilylethylsiloxy groups.

[0069] Said linear polyorganosiloxanes may be oils having a dynamicviscosity at 25° C. of around 1 to 100,000 mPa.s at 25° C., generallyaround 10 to 5000 mPa.s at 25° C., or gums having a molecular mass ofaround 1,000,000.

[0070] When these are cyclic polyorganosiloxanes, they consist ofW₂SiO_(2/2), Y₂SiO_(2/2) and WYSiO_(2/2) “D” units, which may be of thedialkylsiloxy, alkylarylsiloxy, alkylvinylsiloxy, alkylsiloxy oralkylXsiloxy type; examples of such units have already been mentionedabove.

[0071] Said cyclic polyorganosiloxanes B have a viscosity of around 1 to5000 mPa.s.

[0072] The compounds B having aliphatically unsaturated groups, whichare useful within the context of the process according to the invention,are, for example, those having olefinically or acetylenicallyunsaturated groups, these being well known in the technical field inquestion. In this regard, reference may be made to U.S. Pat. Nos.3,159,662, 3,220,272 and 3,410,886 which describe the abovementionedcompounds.

[0073] According to an advantageous variant of the invention, thereaction mixture comprises compounds A and compounds B in an amount suchthat the SiH/unsaturated groups molar ratio is between 0.4 and 10,preferably between 1 and 4 and more preferably still is around 1.7.Furthermore, in practice, within the reaction mixture, at least one ofthe compounds A comprises at least three SiH radicals and at least oneof the compounds B comprises at least two aliphatic reactive groups.

[0074] The thermally activated hydrosilylation reaction conditions arestandard conditions. They are generally catalyzed by heat-sensitiveplatinum complexes. As representatives of these catalysts, mention mayespecially made of Karstedt's catalyst. The catalyst is present in anamount of 1 to 400, preferably from 10 to 300 and more preferably from20 to 200 ppm of platinum metal expressed by weight with respect to thepolyorganosiloxane compound used.

[0075] Apart from this catalyst, the components of the silicone coatingcontain an inhibitor for initiating the reaction. Especially suitable asinhibitors are dialkyl carboxylic esters, such as a dialkyl maleate, orhydroperoxides.

[0076] In a second variant in which the silicone coating derives from adehydrogenocondensation reaction, the polyorganosiloxane derivatives arepreferably chosen so that the polyorganosiloxane derivative possessingat least one reactive SiH radical per molecule is a polyorganosiloxane Aas defined above and the polyorganosiloxane having at least one reactiveSiOH radical per molecule satisfies the definition of thepolyorganosiloxane C described below.

[0077] The compounds C are chosen from polyorganosiloxanes comprising:

[0078] units of the following formula (4): $\begin{matrix}{({OH})_{f}W_{g}^{''}{SiO}_{\frac{4 - {({f + g})}}{2}}} & (4)\end{matrix}$

[0079]  in which:

[0080] the symbols W″, which are similar or different, are by definitionidentical to W according to formula (1),

[0081] f is 1 or 2, g is 0, 1 or 2, with the sum (f+g) having a value ofbetween 1 and 3; and, optionally, other units of formula (2) as definedabove.

[0082] The polyorganosiloxane C may be formed only from units of formula(4) or may also include units of formula (2).

[0083] It may have a linear, branched or unbranched, cyclic or networkstructure. The degree of polymerization is greater than or equal to 2.More generally, it is less than 5000.

[0084] Examples of units of formula (4) are:

HO(CH₃)SiO_(1/2), HOCH₃SiO_(2/2) and HO(C₆H₅)SiO_(2/2).

[0085] When these are linear polymers, they essentially consist ofW″₂SiO_(2/2), W″(OH)SiO_(2/2), and (OH)₂SiO_(2/2) “D” units andW″₃SiO_(1/2) and W″(OH)₂SiO_(1/2) “M” units.

[0086] These linear polyorganosiloxanes may be oils having a dynamicviscosity at 25° C. of around 1 to 100,000 mPa.s at 25° C., generallyaround 10 to 5000 mPa.s at 25° C., or gums having a molecular mass ofaround 1,000,000.

[0087] When these are cyclic polyorganosiloxanes, they consist ofW″₂SiO_(2/2), and W″(OH)SiO_(2/2), (OH)₂SiO_(2/2) “D” units which may beof the dialkylsiloxy or alkylarylsiloxy type. They have a viscosity ofaround 1 to 5000 mPa.s.

[0088] The dynamic viscosity at 25° C. of all the polymers considered inthe present specification may be measured using a Brookfield viscometeraccording to the AFNOR NFT 76 102 standard of February 1972.

[0089] According to an advantageous variant of the invention, thepolyorganosiloxanes A used comprise from 1 to 50 SiH units per molecule.According to an advantageous variant of the invention, thepolyorganosiloxanes C used comprise from 1 to 50 SiOH units permolecule.

[0090] Moreover, in practice, within the reaction mixture, at least oneof the compounds A comprises at least three SiH radicals and at leastone of the compounds C comprises at least two SiOH groups.

[0091] The reaction conditions for dehydrogenocondensation between thepolyorganosiloxane-type monomers, oligomers and/or polymers having SiHunits and the polyorganosiloxane-type monomers, oligomers and/orpolymers having SiOH units are standard conditions, for example bythermal-type activation in the presence of a catalyst (W. Alternoll“Chemistry and Technology of Silicones”, Edition 68, chapter 5, page201-205).

[0092] With regard to the third variant, according to which the coatingderives from the polymerization and/or crosslinking by UV irradiation,thermal activation or by an electron beam of polyorganosiloxanemonomers, oligomers or polymers carrying reactive units of the acrylate,epoxy, oxetane, dioxolane, and/or alkenyl ether type, the latterpolyorganosiloxanes are preferably chosen frompolyorganohydrogenosiloxanes comprising:

[0093] units of the following formula (5): $\begin{matrix}{Z_{h}W_{i}^{\prime\prime\prime}{SiO}_{\frac{4 - {({h + j})}}{2}}} & (5)\end{matrix}$

[0094]  in which:

[0095] the symbols W′″, which are similar and/or different, correspondto the same definition as given for W in formula (1);

[0096] the symbols Z are similar or different and represent:

[0097] a group W′″,

[0098] a hydrogen radical, and/or

[0099] a crosslinkable organofunctional group, preferably an acrylatefunctional, epoxy functional, oxetane functional, dioxolane functionaland/or alkenyl ether functional group, linked to the silicon of thepolyorganosiloxane via a divalent radical containing from 2 to 20 carbonatoms and possibly containing at least one heteroatom, preferablyoxygen,

[0100] with at least one of the symbols Z representing a crosslinkablefunctional organic group;

[0101] h is equal to 1 or 2, i is equal to 0, 1 or 2 with the sum (h+i)having a value of between 1 and 3;

[0102] optionally, other units of formula (2) as defined above.

[0103] According to an advantageous variant of the invention, thepolyorganosiloxanes used contain from 3 to 10 organofunctional groupsper macromolecular chain. For an epoxy functional group, thiscorresponds to epoxyde levels varying from 20 to 2000 molar meq./100 gof polyorganosiloxane.

[0104] As examples of organofunctional radicals, mention may be made ofthose included in the following formulae:

[0105] and their isomers;

 —(O)_(n′)—(CH₂)_(n″)—O—CH═CH₂

—(O)_(n′)—(CH₂)_(n″)—R¹—O—CH═CH₂

—(O)_(n′)—(CH₂)_(n″)—O—CH═CH—R²

[0106] in which:

[0107] n′ represents 0 or 1 and n″ an integer between 1 and 5;

[0108] R¹ represents:

[0109] a C₁-C₁₂ linear, branched or cyclic alkylene radical, optionallysubstituted, or

[0110] a C₅-C₁₂ arylene radical, preferably phenylene, optionallysubstituted, preferably with one to three C₁-C₆ alkyl groups;

[0111] R² represents a C₁-C₆ linear or branched alkyl radical.

[0112] The linear polyorganosiloxanes may be oils having a dynamicviscosity at 25° C. of around 10 to 10 000 mPa.s at 25° C., generally ofaround 20 to 5000 mPa.s at 25° C. and more preferably still 20 to 600mPa.s at 25° C., or gums having a molecular mass of around 1,000,000.

[0113] When these are cyclic polyorganosiloxanes, they consist of unitswhich may, for example, be of the dialkylsiloxy or alkylarylsiloxy type.These cyclic polyorganosiloxanes have a viscosity of around 1 to 5,000mPa.s.

[0114] The dynamic viscosity at 25° C. of all the silicones consideredin the present description may be measured using a Brookfield viscometeraccording to the AFNOR NFT 76 102 standard of February 1972.

[0115] This type of compound is described in particular in the patentsDE-A 4 009 889; EP-A 396 130; EP-A 355 381; EP-A 105 341; FR-A 2 110 115and FR-A 2 526 800.

[0116] The vinyloxy functional polyorganosiloxanes may be prepared, forexample, by a hydrosilylation reaction between oils having SiH units andvinyloxy functional compounds such as allyl vinyl ether and allylvinyloxy ethoxybenzene.

[0117] The epoxy functional polyorganosiloxanes may be prepared, forexample, by a hydrosilylation reaction between oils having SiH units andepoxy functional compounds such as 4-vinylcyclohexene oxide and allylglycidyl ether.

[0118] The oxetane functional polyorganosiloxanes may be prepared, forexample, by hydrosilylation of unsaturated oxetanes or by condensationof oxetanes containing a hydroxy functional group.

[0119] The dioxolane functional polyorganosiloxanes may be prepared, forexample, by hydrosilylation of unsaturated dioxolanes.

[0120] The acrylate functional polyorganosiloxane may be prepared, forexample, by reacting an epoxy functionalized polyorganosiloxane withacrylic acid.

[0121] The UV, thermal or electron-beam crosslinking and/orpolymerization reaction conditions are standard conditions.

[0122] As conventional initiators, those described in patent EP 562 897are especially recommended. They may also be corresponding iodonium orsulfonium salts of hexafluorophosphate or hexafluoroantimonate.

[0123] In this case, the present invention makes it possibleadvantageously to dispense with conventional modulators.

[0124] As representative examples of such modulators, mention may moreparticularly be made of the resins comprising especially M units and Qunits and/or T units. M units are as defined above, Q silicone units areof the SiO_(4/2) type and T units are of the SiO_(3/2)W type, with W asdefined above.

[0125] These resins are in fact resins through which it is possible tovary the level of adhesion of the corresponding silicone coating to agiven substrate.

[0126] Conventionally, it is through the proportion of this type ofresin in a silicone composition that the degree of adhesion of thecorresponding silicone coating to a substrate is adjusted.

[0127] The silicone coating according to the invention may also includeadditives.

[0128] These, for example, may be mineral or non-mineral fillers and/orpigments, such as synthetic or natural fibers, calcium carbonate, talc,clay, titanium dioxide or fumed silica. This may especially allow themechanical properties of the final materials to be improved.

[0129] Soluble dyes, oxidation inhibitors and/or any other material notinterfering with the catalytic activity of the platinum complex and therelease-force-regulating activity of the additive may also be added tothe component of the silicone coating.

[0130] With regard to the adhesive, this is chosen from the adhesivescommonly used for being coated on the surface of a large variety ofmaterials so as to obtain labels, tapes or any other pressure-sensitiveself-adhering material, called PSAs (pressure-sensitive adhesives).These adhesives give the material the ability to adhere to the surfaceof a substrate, without requiring any activation other than slightpressure. PSA-type adhesives may be in solvent form, in aqueous form,and especially in an emulsion phase, and/or in hot-melt form.

[0131] The monomers used to prepare the adhesive are selected accordingto their glass transition temperature, Tg, in order to give the polymersincorporating them the expected behavior in terms of adhesion andviscoelasticity. For this purpose, the monomers advantageously possess aglass transition temperature which is low enough, generally between −70and −10° C., and is preferably less than −30° C.

[0132] More specifically, these monomers are chosen from the groupconsisting of:

[0133] (meth)acrylic esters, such as esters of acrylic acid and ofmethacrylic acid with hydrogenated or fluorinated C₁-C₁₂, preferablyC₁-C₈, alkanols, particularly methyl acrylate, ethyl acrylate, propylacrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate,tert-butyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate,isooctyl acrylate, decyl acrylate, dodecyl acrylate, methylmethacrylate, ethyl methacrylate, n-butyl methacrylate and isobutylmethacrylate;

[0134] vinyl nitriles including more particularly those having from 3 to12 carbon atoms, such as, in particular, acrylonitrile andmethacrylonitrile;

[0135] vinyl esters of carboxylic acid, such as vinyl acetate, vinylversatate and vinyl propionate;

[0136] ethylenically unsaturated monocarboxylic and dicarboxylic acids,such as acrylic acid, methacrylic acid, itaconic acid, maleic acid andfumaric acid, and monoalkyl and dialkyl esters of monocarboxylic anddicarboxylic acids of the type mentioned with alkanols preferably havingfrom 1 to 8 carbon atoms and their N-substituted derivatives;

[0137] amides of unsaturated carboxylic acids, such as acrylamide,methacrylamide, N-methylolacrylamide or methacrylamide, andN-alkylacrylamides;

[0138] ethylenic monomers containing a sulfonic acid group and itsammonium or alkali metal salts, for example vinylsulfonic acid,vinylbenzenesulfonic acid, alpha-acrylamidomethylpropanesulfonic acidand 2-sulfoethylene methacrylate;

[0139] unsaturated ethylenic monomers containing a secondary, tertiaryor quaternary amino group, or a heterocyclic group containing nitrogen,such as, for example, vinylpyridines, vinylimidazole, aminoalkyl(meth)acrylates and aminoalkyl (meth)acrylamides such asdimethylaminoethyl acrylate or dimethylaminoethyl methacrylate,di-tert-butylaminoethyl acrylate or di-tert-butylaminoethyl methacrylateand dimethylaminomethylacrylamide or dimethylaminomethylmethacrylamide;

[0140] zwitterionic monomers such as, for example,sulfopropyl(dimethyl)aminopropyl acrylate;

[0141] ethylenic monomers carrying a sulfate group;

[0142] ethylenic monomers carrying one or more phosphate and/orphosphonate functional groups; and

[0143] mixtures thereof.

[0144] Preferably, the PSAs are predominantly obtained by thepolymerization of alkyl acrylate monomers such as alkyl (meth)acrylatemonomers, which are generally present in an amount from 50 to about 99%and preferably in an amount from 80 to 99% by weight, and ofcopolymerizable polar monomers, such as, for example, acrylic acid, insmaller proportions.

[0145] More preferably, the monomers are chosen from 2-ethylhexylacrylate, butyl acrylate, hexyl acrylate, heptyl acrylate, octylacrylate, isooctyl acrylate, decyl acrylate, isobutyl acrylate, dodecylacrylate or mixtures thereof, or methacrylates such as n-butylmethacrylate, methacrylic acid, acrylic acid, itaconic acid, maleic acidand/or acrylamide.

[0146] The PSAs may, of course, be used in a formulated form, that is tosay blended with conventional additives for adhesives, such as wettingagents, tackifiers, etc.

[0147] Conventionally, the complexes according to the invention mayfurthermore include one or more additives chosen depending on theintended final application.

[0148] The additives may especially be compounds, optionally in the formof polymers, having mobile hydrogens, such as alcohols, glycols andpolyols, useful for improving the flexibility in particular of thesilicone matrix after polymerization and/or crosslinking; mention may bemade, for example, of polycaprolactone-polyols, in particular thepolymer obtained initially from2-ethyl-2-(hydroxymethyl)-1,3-propanediol and from 2-oxepanone, such asthe product TONE POLYOL-301 sold by Union Carbide, or the othercommercial polymers TONE POLYOL 201 and TONE POLYOL 12703 from UnionCarbide. Mention may also be made, as additives, of long-chain alkyldiacids, fatty esters of unsaturated acids which may or may not beepoxidized, for example epoxidized soybean oil or epoxidized linseedoil, epoxidized 2-ethylhexyl ester, 2-ethylhexyl epoxystearate, octylepoxystearate, epoxidized acrylic esters, epoxidized soybean oilacrylates, epoxidized linseed oil acrylates, diglycidyl ether ofpolypropylene glycol, long-chain aliphatic epoxides, etc.

[0149] Irrespective of the nature of the polymerizable matrix, they mayalso be, for example: fillers such as, in particular, ground natural orsynthetic (polymeric) fibers, calcium carbonate, talc, clay, titaniumdioxide, precipitated silica or pyrogenic silica; soluble dyes;oxidation and corrosion inhibitors; organosilicic or nonorganosilicicadhesion promoters; fungicides, bactericides, antimicrobial agents;and/or any other material not interfering with the activity of theadditive according to the invention.

[0150] The amounts of coating deposited on the substrates can vary.

[0151] The amounts of silicone coating usually range from 0.1 to 5 g/m²of surface treated. These amounts depend on the nature of the substratesand on the desired nonstick properties. They are usually between 0.5 and1.5 g/m² in the case of nonporous substrates.

[0152] With regard to the amounts of adhesive coating, these arepreferably less than 200 g/m² and more preferably less than 100 g/m².

[0153] The substrates may be a metal material, such as tinplate, andpreferably a cellulosic material of the paper or board type for example,or a polymeric material of the vinyl type. Thermoplastic polymericfilms, such as polyethylene, polypropylene or polyester films, areparticularly advantageous.

[0154] In the embodiment in which the adhesive coating is in contactwith a substrate consisting of a second material, this second materialmay be chosen from the materials proposed for the first substrate andmay or may not be identical in nature to the first substrate. Theadhesive coating may be applied in various ways. In particular it may bedeposited by transfer.

[0155] Finally, the substrate to which the silicone coating and/or theadhesive coating are/is applied may already have been coated with aninitial coating on which a coating according to the invention issuperimposed, provided that this attached coating is transparent toelectron-beam irradiation.

[0156] One other subject of the present invention is also the articles(for example sheets and tapes) comprising a complex according to theinvention. These may especially be labels, self-adhesive sheets oradhesive tapes.

[0157] A second aspect of the present invention relates to the use of anadditive as defined above, in a silicone coating according to theinvention, intended to form a silicone/adhesive complex, as definedabove, in order to vary the forces to release a silicone/adhesiveinterface by activating said additive by electron-beam irradiation.

[0158] More specifically, the subject of the present invention is theuse of at least one organic (meth)acrylate derivative, an alkenyl etherand/or a silicone having one or more (meth)acrylate functional groupsand/or one or more alkenyl ether functional groups, that can beactivated by an electron-beam source, in a silicone-based compositionaccording to the present invention, as an additive for regulating theadhesion of the corresponding silicone coating to a substrate,preferably an adhesive substrate as defined above.

[0159] Advantageously, the claimed use makes it possible to vary,depending on the irradiation applied, by means of an electron-beamsource, the release force manifested by the silicone coatingincorporating said additive, with respect to a substrate and preferablyan adhesive coating according to the invention.

[0160] As regards more particularly the specific characteristics of saidadditive and of the silicone coatings or adhesives in terms of chemicalcomposition, quantity, method of preparation and/or activation,reference should be made to the foregoing text.

[0161] The examples and figures which follow are given by way ofillustration and imply no limitation of the present invention.

[0162] Equipment and Method

[0163] A silicone formulation consisting of the cationic UV system(SILCOLEASE POLY® and SILCOLEASE CATA211® oil sold by Rhodia Chimie)with two types of additives according to the invention was used. Thesewere:

[0164] a silicone oil with acrylate functional groups: SILCOLEASE 21621®resin.

[0165] an acrylic organic monomer: trimethylpentanediol triacrylate(TMPTA).

[0166] These additives may represent up to 50% by weight of thecoatiing.

EXAMPLE 1

[0167] The cationic UV fomulation tested was the following: Formulation1 Formulation 2 SILCOLEASE 90 90 POLY 200‘® SILCOLEASE 21621 ® 10 resinSILCOLEASE 2.5 2.5 CATA 211 ®

[0168] The formulations were coated at a rate of 50 m/min on an OPP CR50film (polypropylene film) from UCB using a Rotomec pilot coater. Thesilicone coating was crosslinked by passing it beneath an 80 W/cm UVfusion lamp (H+ tube). The coatings deposited were around 1.2 g/m² inorder to ensure good coverage of the substrate. The coating on thesubstrate and the curing of the mixtures posed no problems. Nomanifestation of an oily appearance, of prewetting or of stickiness tothe touch was observed.

[0169] The coatings obtained were then adhesive-coated with theacrylic-type adhesive TESA® 4970. The complex was then subjected toirradiation from an EB source through the siliconized OPP film.

[0170] Six irradiation conditions were applied, the dose received by thespecimen being expressed by kGray and depending on the speed at which itpasses beneath the source and on the adjustment of the current.

[0171] Table 1 shows the various adjustment conditions for the electronbeam (EB) generator and the doses received by the specimen. Thisirradiation took place through the substrate film and the siliconelayer. The EB source was of the IRELEC® brand. Its acceleration voltagewas between 200 and 400 keV and the filament current was between 0 to 10mA. The specimen was transported beneath the electron beam at speeds ofbetween 0.15 and 8 m/mn by means of a conveyer. By adjusting theacceleration voltage, the filament current and the conveying speed, itis possible to adjust the irradiation dose between a few kGrays and ahundred kGrays or so. TABLE 1 Test Test Test Test Test Test Conditions 12 3 4 5 6 Current in mA 2.5 2.5 2.5 2.5 7.5 5 Speed of pass beneath 8 10.7 0.56 1.5 1 the beam in m/min Irradiation energy 5 44 90 130 128 131in kilograys

[0172] Within hours following the EB irradiation, the complex wasseparated by a 180° peel test at a rate of 300 mm/min as described inthe FINAT3 standard. The peel forces obtained are given in Table 2below. As a comparison, a formulation without an additive was alsotested. TABLE 2 TESA 4970 ADHESION FORCE IN g/cm Silicone No Test TestTest Test Test Test formulations irradiation 1 2 3 4 5 6 Formulation 1:8.4 16.3 23.7 28.3 50 38.9 48.8 POLY 200 ® + CATA 211 ® (control)Formulation 2: 9.6 17.4 65 80.8 94.5 90.1 104.1 POLY 200 ® + CATA211 ® + 10% SILCOLEASE 21621 ® resin (trial 1)

[0173] It may be seen that the irradiation causes an increase in therelease force in the case of the formulation containing an additive.Forces of 80 g/cm were achieved for a dose of 90 kGray. Note there is amodulating effect with the formulation not containing an additive, butthis effect is of a much smaller magnitude; it is obtained with greaterirradiation doses.

EXAMPLE 2

[0174] The formulation tested was a SILCOLEASE CATA 211®/SILCOLEASE POLY200® formulation. The modulating additive used was TMPTA.

[0175] The TMPTA was added at two levels: 0.34 and 5%. The 0.34% mixturewas miscible, whereas the 5% mixture was immiscible. The details of theformulations evaluated are given below. Formulation 1: Formulation 3:Formulation 4: No additive 0.34% of TMPTA 5% of TMPTA SILCOLEASE 100 10095 POLY 200 ® TMPTA 0.34 5 SILCOLEASE 2.5 2.5 2.5 CATA 211 ®

[0176] The processing conditions were the same as in the previous trial.

[0177] As previously, these coatings were adhesive-coated with the TESA4970® adhesive and then the complex was irradiated under variousconditions, which are those given in table 1 of example 1. The adhesionforce of the TESA 4970® was then measured using a 180° peel test. Theresults obtained are given in table 3. TABLE 3 TESA 4970 ADHESION FORCEIN g/cm Silicone No Test Test Test Test Test Test formulationsirradiation 1 2 3 4 5 6 Formulation 1: 8.4 16.3 23.7 28.3 50 38.9 48.8POLY 200 ® + CATA 211 ® (control) Formulation 4: 14.1 27.5 85.1 92.698.5 90.7 93.4 POLY 200 ® + CATA 211 ® + 5% TMPTA (Trial 2) Formulation3: 16 19.7 36.7 57.2 87.9 59.2 68.1 POLY 200 ® + CATA 211 + 0.34% TMPTA(Trial 3)

[0178] It will be noted that there is an increase in the peel force withirradiation current for the systems containing additives. The modulatingeffect depends directly on the amount of TMPTA.

EXAMPLE 3

[0179] A standard thermally crosslinkable silicone formulation(vinyl-type oil/SiH-type crosslinking oil/platinum catalyst) was used.As modulating additive, SILCOLEASE 21621® resin was added to thisformulation.

[0180] The tested formulation therefore comprised the SILCOLEASE 11365®resin (SiVi functionalized PMDS oil)/the crosslinking agent SILCOLEASE12031® (SiH functionalized PMDS oil) and the Karstedt platinum catalystSILCOLEASE CATA 12070®. The exact composition was adjusted in order tohave an SiH/SiVi ratio of 1.7 and the amount of Pt was about 100 ppm.10% of the SILCOLEASE 21621® resin was added to this formulation. Thedetails of the formulation were as follows: Formulation 5: Formulation6: no additive with additive SILCOLEASE 11365 ® 100 90 resin SILCOLEASE21621 ® 10 resin SILCOLEASE 12031 ® 2.5 2.2 crosslinking agentSILCOLEASE 12070 ® 5 5 catalyst

[0181] These formulations were coated at a rate of 50 m/min on an OPPCR50 film (polypropylene film) from UCB using a Rotomec pilot coater.The siliconized coating was crosslinked by passing it through a thermaloven heated to 150° C. The coatings deposited were around 1.2 g/m² inorder to ensure good coverage of the substrate.

[0182] The coating and the crosslinking on the OPP substrate posed noproblem: no manifestation of an oily appearance, of dewetting or ofstickiness to the touch.

[0183] The coatings obtained were then adhesive-coated with the TESA4970® adhesive. The complex was subjected to an irradiation from an EBsource under the conditions given in table 1 of example 1. Thisirradiation was carried out through the support film and the siliconelayer. Within hours following the EB irradiation, the complex wasseparated by a 180° peel test at a rate of 300 mm/min as described inthe FINAT3 standard. The peel forces obtained are given in Table 3.TABLE 3 TESA 4970 ADHESION FORCE IN g/cm No Test Test Test Test TestTest irradiation 1 2 3 4 5 6 Formulation 5 4.6 6.7 11.4 14.7 18.5 18.418.9 Formulation 6 2.8 7.7 45.7 78.4 66.4 72.2 78.1

[0184] It will be noted in all cases that the level of adhesion of thePSA is increased after irradiation. This adhesion force depends on theenergy delivered by the EB source.

EXAMPLE 4

[0185] A standard UV radical crosslinking formulation consisting of anacrylate oil and a radical photoinitiator was used.

[0186] The formulation consisted of the oil SILCOLEASE 21621 with, ascatalyst, DAROCURE 1173® from Ciba Specialties. The details of theformulations are as follows: Formulation 7 SILCOLEASE 21621 ® resin 98DAROCURE 1173 ® 2

[0187] The formulations were coated using a Meyer bar on an OPP CR50film (polypropylene film) from UCB. The siliconized coating wascrosslinked by passing it beneath a UV IST lamp with a power of 80 W/cmat a speed of 10 m/min. To ensure proper curing, the coating was in anitrogen atmosphere.

[0188] The coatings deposited were around 1.2 g/m² in order to ensuregood coverage of the substrate. The coating on the substrate and thecuring of the compounds posed no problem: no manifestation of an oilyappearance, of dewetting or of stickiness to the touch.

[0189] The coatings obtained were then adhesive-coated with the TESA4970® adhesive. The complex was then subjected to irradiation from an EBsource. The six irradiation conditions are described in table 1 ofexample 1. The irradiation was carried out through the support film andthe silicone layer.

[0190] Within hours following the EB irradiation, the complex wasseparated by a 180° peel test at a rate of 300 mm/min as described inthe FINAT3 standard. The peel forces obtained are given in the tablebelow. TABLE 5 TESA 4970 ADHESION FORCE IN g/cm No Test Test Test TestTest Test irradiation 1 2 3 4 5 6 Formulation 7: 9.6 30 80 100 120 120140 SILCOLEASE 21621 ® resin + DAROCURE 1173 ®

1. A silicone/adhesive complex comprising at least one silicone coatingapplied to a first substrate and an adhesive coating applied to a secondsubstrate, the force to release a silicone/adhesive interface of whichcan be varied, characterized in that said silicone coating comprises atleast one additive for regulating the force to release asilicone/adhesive interface and the activity of which is initiated andable to be varied by electron-beam irradiation.
 2. The complex asclaimed in claim 1, characterized in that the two substrates consist oftwo separate entities placed so that the silicone coating of the firstsubstrate is in contact with the adhesive coating of the secondsubstrate.
 3. The complex as claimed in claim 1, characterized in thatthe two substrates each consist respectively of the two faces of thesame entity.
 4. The complex as claimed in one of claims 1 to 3,characterized in that the activity of the additive for regulating therelease force is initiated and can be varied by exposing at least thesilicone/adhesive interface to at least one electron-beam irradiation.5. The complex as claimed in one of the preceding claims, characterizedin that the additive for regulating the force to release thesilicone/adhesive interface adopted within the context of the presentinvention is chosen from: (i) organic (meth)acrylate derivatives; (ii)alkenyl ethers; and (iii) silicones having one or more (meth)acrylateand/or alkenyl ether functional groups.
 6. The complex as claimed in oneof claims 1 to 5, characterized in that the additive for regulating therelease force is a silicone having one or more (meth)acrylate and/oralkenyl ether functional groups.
 7. The complex as claimed in claim 6,characterized in that the silicones with (meth)acrylate functionalgroups are chosen from organopolysiloxanes having acrylate,methacrylate, (meth)acrylate ether and meth(acrylate)ester functionalgroups linked to the polysiloxane chain via a SiC bond.
 8. The complexas claimed in claim 6, characterized in that the silicones with alkenylether functional groups are derived from a hydrosilylation reactionbetween oils containing SiH structural units and compounds carryingalkenyl ether functional groups such as allyl vinyl ethers, allylvinyloxy ethoxybenzene and the like.
 9. The complex as claimed in one ofthe preceding claims, characterized in that the additive for regulatingthe release force is employed in an amount from 0.1 to 20% by weight ofthe total silicone mixture.
 10. The complex as claimed in one of thepreceding claims, characterized in that the silicone coating derivesfrom the polymerization and/or crosslinking of polyorganosiloxanemonomers, oligomers and/or polymers
 11. The complex as claimed in claim10, characterized in that the polymerization and/or crosslinking derivesfrom hydrosilylation between, on the one hand, monomers, oligomersand/or polymers carrying reactive SiH structural units and, on the otherhand, monomers, oligomers and/or polymers carrying an unsaturatedaliphatic reactive group.
 12. The complex as claimed in claim 11,characterized in that the polyorganosiloxane having at least onereactive SiH radical per molecule is a polyorganohydrogenosiloxane Acomprising: units of formula (1): $\begin{matrix}{H_{a}W_{b}{SiO}_{\frac{4 - {({a + b})}}{2}}} & (1)\end{matrix}$

 in which: the symbols W, which are similar and/or different, represent:a linear or branched alkyl radical containing 1 to 18 carbon atoms,optionally substituted with at least one halogen, preferably fluorine,the alkyl radicals preferably being methyl, ethyl, propyl, octyl and3,3,3-trifluoropropyl, a cycloalkyl radical containing between 5 and 8cyclic carbon atoms, optionally substituted with at least one halogen,preferably fluorine an aryl radical containing between 6 and 12 carbonatoms which may optionally be substituted on the aryl part withhalogens, alkyls and/or alkoxyls containing 1 to 3 carbon atoms,preferably phenyl or dichlorophenyl or an arylalkyl part having an alkylpart containing between 5 and 14 carbon atoms and an aryl partcontaining between 6 and 12 carbon atoms, optionally substituted on thearyl part by halogens, alkyls and/or alkoxyls containing 1 to 3 carbonatoms, a is 1 or 2, b is 0, 1 or 2, with the sum (a+b) having a value ofbetween 1 and 3; and optionally, other units of average formula (2):$\begin{matrix}{{Wc}\quad {SiO}_{\frac{4 - c}{2}}} & (2)\end{matrix}$

in which W has the same meaning as above and c has a value of between 0and
 3. 13. The complex as claimed in claim 12, characterized in that thepolyorganosiloxanea A are chosen from: dimethylpolysiloxanes havinghydrogenodimethylsilyl end groups; dimethylhydrogenomethylpolysiloxanecopolymers having trimethylsilyl end groups;dimethylhydrogenomethylpolysiloxane copolymers havinghydrogenodimethylsilyl end groups; hydrogenomethylpolysiloxanes havingtrimethylsilyl end groups; and cyclic hydrogenomethylpolysiloxanes. 14.The complex as claimed in one of claims 11 to 13, characterized in thatthe polyorganosiloxane having at least one unsaturated aliphaticreactive group per molecule is a polyorganosiloxane B comprising similaror different units of formula (3): $\begin{matrix}{W_{d}^{\prime}Y_{e\quad}{SiO}_{\frac{4 - {({d + e})}}{2}}} & (3)\end{matrix}$

in which: the symbols W′, which are similar and/or different, represent:a linear or branched alkyl radical containing 1 to 18 carbon atoms,optionally substituted with at least one halogen, preferably fluorine,the alkyl radicals preferably being methyl, ethyl, propyl, octyl and3,3,3-trifluoropropyl, a cycloalkyl radical containing between 5 and 8cyclic carbon atoms, optionally substituted with at least one halogen,preferably fluorine, an aryl radical containing between 6 and 12 carbonatoms which may optionally be substituted on the aryl part withhalogens, alkyls and/or alkoxyls containing 1 to 3 carbon atoms,preferably phenyl or dichlorophenyl, an arylalkyl part having an alkylpart containing between 5 and 14 carbon atoms and an aryl partcontaining between 6 and 12 carbon atoms, optionally substituted on thearyl part with halogens, or alkyls and/or alkoxyls containing 1 to 3carbon atoms, the symbols Y are similar or different and represent aC₁-C₁₂ linear or branched alkenyl residue having at least oneethylenically unsaturated group at the chain end and/or in the chain,and optionally at least one heteroatom; e is equal to 1 or 2, d is equalto 0, 1 or 2 with the sum (d+e) having a value of between 1 and 3; and,optionally, other units of average formula (2): $\begin{matrix}{{Wc}\quad {SiO}_{\frac{4 - c}{2}}} & (2)\end{matrix}$

in which W satisfies the definition proposed for W′ and c has a value ofbetween 0 and
 3. 15. The complex as claimed in one of claims 11 to 14,characterized in that the silicone coating comprises compounds A andcompounds B in an amount such that the SiH/unsaturated group molar ratiois between 0.4 and 10 and preferably is about 1.7.
 16. The complex asclaimed in one of claims 11 to 15, characterized in that the siliconecoating furthermore includes a catalyst of the heat-sensitive platinumcomplex type.
 17. The complex as claimed in one of claims 11 to 16,characterized in that the silicone coating furthermore includes aninhibitor for the reaction.
 18. The complex as claimed in one of claims1 to 10, characterized in that the silicone coating derives fromdehydrogenocondensation between, on the one hand, a polyorganosiloxanederivative A having at least one reactive SiH radical per molecule and,on the other hand, a polyorganosiloxane having at least one reactiveSiOH radical per molecule.
 19. The complex as claimed in claim 18,characterized in that the polyorganosiloxane possessing at least onereactive SiH radical per molecule is a polyorganosiloxane A as definedin claim 12 or
 13. 20. The complex as claimed in claim 18 or 19,characterized in that the polyorganosiloxane derivatives (C) are chosenfrom polyorganosiloxanes comprising: units of the following formula (4):$\begin{matrix}{({OH})_{f}W_{g}^{''}{SiO}_{\frac{4 - {({f + g})}}{2}}} & (4)\end{matrix}$

 in which: the symbols W″, which are similar or different, represent: alinear or branched alkyl radical containing 1 to 18 carbon atoms,optionally substituted with at least one halogen, preferably fluorine,the alkyl radicals preferably being methyl, ethyl, propyl, octyl and3,3,3-trifluoropropyl, a cycloalkyl radical containing between 5 and 8cyclic carbon atoms, optionally substituted with at least one halogen,preferably fluorine, an aryl radical containing between 6 and 12 carbonatoms which may optionally be substituted on the aryl part withhalogens, alkyls and/or alkoxyls containing 1 to 3 carbon atoms,preferably phenyl or dichlorophenyl, or an arylalkyl part having analkyl part containing between 5 and 14 carbon atoms and an aryl partcontaining between 6 and 12 carbon atoms, optionally substituted on thearyl part with halogens, alkyls and/or alkoxyls containing 1 to 3 carbonatoms, f is 1 or 2, g is 0, 1 or 2, with the sum (f+g) having a value ofbetween 1 and 3; and, optionally, other units of formula (2):$\begin{matrix}{WcSiO}_{\frac{4 - c}{2}} & (2)\end{matrix}$

in which W satisfies the definition proposed for W″ and c has a value ofbetween 0 and
 3. 21. The complex as claimed in one of claims 18 to 20,characterized in that the polyorganosiloxanes A used comprise from 1 to50 SiH units per molecule and the polyorganosiloxanes C used comprisefrom 1 to 50 SiOH units per molecule.
 22. The complex as claimed in oneof claims 1 to 10, characterized in that the silicone coating derivesfrom the polymerization and/or crosslinking by UV irradiation, thermalactivation or by an electron beam of polyorganosiloxane monomers,oligomers or polymers carrying reactive units of the acrylate, epoxy,oxetane, dioxolane and/or alkenyl ether type.
 23. The complex as claimedin claim 22, characterized in that the polyorganohydrogenosiloxanescomprise: units of formula (5): $\begin{matrix}{Z_{h}W_{i}^{\prime\prime\prime}{SiO}_{\frac{4 - {({h + j})}}{2}}} & (5)\end{matrix}$

 in which: the symbols W′″, which are similar and/or different,represent: a linear or branched alkyl radical containing 1 to 18 carbonatoms, optionally substituted with at least one halogen, preferablyfluorine, the alkyl readicals preferably being methyl, ethyl, propyl,octyl and 3,3,3-trifluoropropyl, a cycloalkyl radical containing between5 and 8 cyclic carbon atoms, optionally substituted with at least onehalogen, preferably fluorine, an aryl radical containing between 6 and12 carbon atoms which may optionally be substituted on the aryl partwith halogens, alkyls and/or alkoxyls containing 1 to 3 carbon atoms,preferably phenyl or dichlorophenyl, or an arylalkyl part having analkyl part containing between 5 and 14 carbon atoms and an aryl partcontaining between 6 and 12 carbon atoms, optionally substituted on thearyl part with halogens, alkyls and/or alkoxyls containing 1 to 3 carbonatoms, the symbols Z are similar or different and represent: a groupW′″, a hydrogen radical, and/or a crosslinkable organofunctional group,preferably an acrylate functional, epoxy functional, oxetane functional,dioxolane functional and/or alkenyl ether functional group, linked tothe silicon of the polyorganosiloxane via a divalent radical containingfrom 2 to 20 carbon atoms and possibly containing at least oneheteroatom, preferably oxygen, with at least one of the symbols Zrepresenting a crosslinkable functional organic group; h is equal to 1or 2, i is equal to 0, 1 or 2 with the sum (h+i) having a value ofbetween 1 and 3; optionally, other units of formula (2): $\begin{matrix}{WcSiO}_{\frac{4 - c}{2}} & (2)\end{matrix}$

in which W satisfies the definition proposed for W′″ and c has a valueof between 0 and
 3. 24. The complex as claimed in claim 22 or 23,characterized in that the polyorganosiloxanes used contain from 3 to 10organofunctional groups per macromolecular chain.
 25. The complex asclaimed in one of claims 22 to 24, characterized in that theorganofunctional groups are chosen from:

and their isomers

—(O)_(n′)—(CH₂)_(n″)—O—CH═CH₂—(O)_(n′)—(CH₂)_(n″)—R¹—O—CH═CH₂—(O)_(n′)—(CH₂)_(n″)—O—CH═CH—R²in which: n′ represents 0 or 1 and n″ an integer between 1 and 5; R¹represents: a C₁-C₁₂ linear, branched or cyclic alkylene radical,optionally substituted, or a C₅-C₁₂ arylene radical, preferablyphenylene, optionally substituted, preferably with one to three C₁-C₆alkyl groups; R² represents a C₁-C₆ linear or branched alkyl radical.26. The complex as claimed in one of the preceding claims, characterizedin that the adhesive coating derives from a pressure-sensitive adhesiveemulsion.
 27. The complex as claimed in claim 26, characterized in thatthe pressure-sensitive adhesive emulsions are obtained by polymerizationof monomers having a glass transition temperature of between −70° C. and−10° C.
 28. The complex as claimed in claim 27, characterized in thatthe monomers are chosen from the group consisting of: (meth)acrylicesters, such as esters of acrylic acid and of methacrylic acid withhydrogenated or fluorinated C₁-C_(l2), preferably C₁-C₈, alkanols,particularly methyl acrylate, ethyl acrylate, propyl acrylate, n-butylacrylate, isobutyl acrylate, 2-ethylhexyl acrylate, tert-butyl acrylate,hexyl acrylate, heptyl acrylate, octyl acrylate, isooctyl acrylate,decyl acrylate, dodecyl acrylate, methyl methacrylate, ethylmethacrylate, n-butyl methacrylate and isobutyl methacrylate; vinylnitriles including more particularly those having from 3 to 12 carbonatoms, such as, in particular, acrylonitrile and methacrylonitrile;vinyl esters of carboxylic acid, such as vinyl acetate, vinyl versatateand vinyl propionate; ethylenically unsaturated monocarboxylic anddicarboxylic acids, such as acrylic acid, methacrylic acid, itaconicacid, maleic acid and fumaric acid, and monoalkyl and dialkyl esters ofmonocarboxylic and dicarboxylic acids of the type mentioned withalkanols preferably having from 1 to 8 carbon atoms and theirN-substituted derivatives; amides of unsaturated carboxylic acids, suchas acrylamide, methacrylamide, N-methylolacrylamide or methacrylamideand N-alkylacrylamides; ethylenic monomers containing a sulfonic acidgroup and its ammonium or alkali metal salts, for example vinylsulfonicacid, vinylbenzenesulfonic acid, alpha-acrylamidomethylpropanesulfonicacid and 2-sulfoethylene methacrylate; unsaturated ethylenic monomerscontaining a secondary, tertiary or quaternary amino group, or aheterocyclic group containing nitrogen, such as, for example,vinylpyridines, vinylimidazole, aminoalkyl (meth)acrylates andaminoalkyl (meth)acrylamides such as dimethylaminoethyl acrylate ordimethylaminoethyl methacrylate, di-tert-butylaminoethyl acrylate ordi-tert-butylaminoethyl methacrylate and dimethylaminomethylacrylamideor dimethylaminomethylmethacrylamide; zwitterionic monomers such as, forexample, sulfopropyl(dimethyl)aminopropyl acrylate; ethylenic monomerscarrying a sulfate group; ethylenic monomers carrying one or morephosphate and/or phosphonate functional groups; and mixtures thereof.29. An article characterized in that it comprises a complex as claimedin one of the preceding claims.
 30. The article as claimed in claim 29,characterized in that it is a label, a self-adhesive sheet or anadhesive tape.
 31. The use of an additive as defined in claims 5 to 9 ina silicone coating as defined in claims 10 to 25 and intended to form asilicone/adhesive complex as claimed in one of claims 1 to 28 in orderto vary the force to release a silicone/adhesive interface byelectron-beam irradiation of said additive.